1. Field of the Invention
The present invention relates to a valve device for use in a fluid conduit of a semiconductor manufacturing apparatus and the like, a fluid control apparatus with the valve device, and a semiconductor manufacturing apparatus with the fluid control apparatus.
2. Description of the Related Art
There has conventionally been proposed a pneumatically-actuated diaphragm valve device in which a bonnet and a cap accommodating a stem and a piston are connected to a body having a fluid passage and in which the cap is provided with a female screw portion for mounting a tube fitting onto the cap, the stem and the piston being driven by operation air (see Japanese Patent Application Laid-open No. 2014-9765, for example). The tube fitting has a screw unit having a metal male screw portion and a fitting mounted on the screw unit, wherein the male screw portion of the screw unit is threaded into the female screw portion of the valve device to be mounted onto the valve device.